City may have things just a touch easier, given that they face a Barcelona side struggling for form in La Liga, but it will still take some performance to overturn a 2-0 deficit
at the Camp Nou.

But Champions League history does provide reasons to be cheerful. Here are five unlikely comebacks from the last few years, as chosen by Sheridan Bird:

Juventus v Manchester United - 1998/99 semi-finals

Ryan Giggs’ injury time leveller scraped a 1-1 draw for Manchester United against Juventus in the semi-final first leg. The Bianconeri
were optimistic about the return. After barely ten minutes in Turin two Pippo Inzaghi strikes gave the 1996, ‘97 and ‘98 finalists a 3-1 lead on aggregate (including an away goal).

Then, in a display which still renders United fans teary, captain Roy Keane took control. He nullified Edgar Davids and Zinedine Zidane. He headed a goal to re-open the tie. He mastered his emotions to ignore a yellow card which eventually cost him his place in the final.

The Irish midfielder’s energy and belief transmitted to his teammates and intimidated Juve. Goals from Dwight Yorke and Andy Cole sealed a miraculous 3-2 win. The other, more famous, United comeback in the final against Bayern Munich would never have happened without Keano’s Italian job.

Deportivo La Coruna v Milan - 2003/04 quarter-finals

Younger readers might be surprised, but Milan used to be good. In fact not good: the best. They won the 2002/03 Champions League. Shortly after coach Carlo Ancelotti signed Kaka and they got better. When they thrashed Deportivo La Coruna 4-1 in the 2003/04 Champions League quarter-final first leg their grip on the European Cup appeared unbreakable.

But in the second leg the Rossoneri came unstuck in a Galician storm. Depor forwards Alberto Luque and Walter Pandiani tormented the usually impeccable Paolo Maldini and Alessandro Nesta. Juan Carlos Valeron overshadowed Andrea Pirlo. The holders were blown away 4-0, losing 5-4 on aggregate. Maldini said “sometimes the other team has a perfect night.” Depor keeper Molina added: “Sometimes in football you think you have everything. Then someone punches you in the face.”

Monaco v Real Madrid - 2003/04 quarter-finals

That same season Real Madrid’s Galacticos were cruising to the semi-finals after a 4-2 home win against Monaco. Local press and fans, spellbound by Figo, Raul, Zidane and Ronaldo, barely noticed the away goals.

In the second leg Raul scored the opener to put Los Blancos
5-2 up. But the men from the posh principality didn’t whither. Although Ludovic Giuly scored twice, Fernando Morientes was the story. The striker, banished to Ligue 1 on loan by Madrid, headed a trademark goal in a 3-1 win to eliminate his Spanish paymasters on away goals. The unwanted marksman, who also scored in the first game at the Bernabeu, said: “It wasn’t revenge, I had to play and beat friends. I am professional.”

Liverpool v Milan - 2004/05 Final

We all know how this mental night in Istanbul ended. But you might not know that coach Carlo Ancelotti considered this Milan team more skilful than Arrigo Sacchi’s legendary 1980s Rossoneri
(which he played in).

Kaka, Hernan Crespo and Andriy Shevchenko monstered Liverpool in the first half. But a mixture of guts, opportunism and Rafa Benitez tweaks wiped out Milan’s 3-0 lead after the interval. Victory on penalties completed the Redmen’s unbelievable comeback. Days later, at the end of a political summit, international reporters asked Silvio Berlusconi for extra-time for a few more questions. The prime minister and Milan supremo said with a sad smile “we don’t like to talk about extra-time at the moment.”

Chelsea v Napoli - 2011/12 Round of 16

The Andres Villas-Boas Chelsea era hit rock bottom in the stadium under the volcano. Hampered by bad blood and poor form, the Blues
fell apart in Naples in the round of 16 first leg.

In a show of authority, Villas-Boas relegated Frank Lampard and Ashley Cole to the bench (that was a shock two seasons ago). Ezequiel Lavezzi and Edinson Cavani condemned AVB’s side to a seemingly fatal 3-1 defeat.

Right place, right time: Branislav Ivanovic wins it for Chelsea

By the return AVB was gone and the popular Roberto Di Matteo had taken his place. The team looked solid, united and hungry. Travel sickness struck the Neapolitans. La Stampa wrote “Napoli only looked themselves for the first twenty minutes.” A 3-1 Chelsea win forced extra-time, where strongman Branislav Ivanovic turned saviour to score a fourth. The Londoners lived to fight another day… and win the cup.